An organic EL device, which is a display device, is a light emitting element exploiting electro-luminescence of organic compounds. An organic EL device has a cathode, an anode, and an electroluminescent organic light emitting layer provided between the electrodes. Organic light emitting layer can be roughly classified into two categories: the organic light emitting layer containing combinations of small molecular organic compounds (host material and dopant material) and the organic light emitting layer containing polymer. Examples of electro-luminescent polymer include polyphenylenevinylene (also referred to as PPV) and its derivatives. Organic EL devices using polymer can be driven with a relatively low voltage, consumes small power and is suitable for manufacturing a larger display panel, and therefore is presently studied actively.
In an organic EL display panel using organic EL devices, organic EL elements (sub pixels) are arranged in matrix form on the substrate. In an organic EL display panel, organic EL element emits red (R), green (G), or blue (B) light.
An organic light emitting layer containing polymer is formed by applying a polymer ink containing, for example, organic light emitting materials and solvents, to an anode with ink jet or the like. Therefore, when an ink that contains an organic light emitting material is applied to each sub pixel of an organic EL display panel, it is necessary to prevent ink from intruding into adjacent sub pixels.
As a method for preventing an ink from intruding into adjacent sub pixels, defining sub pixels by banks and applying an ink inside region defined by the banks, is known (e.g. see Patent Document 1).
Patent Document 1 discloses a method for preventing a polymer ink from intruding into adjacent sub pixels by providing banks defining each sub pixel and by dropping a polymer ink accurately on each sub pixel.
Further, a technique of making the surface of an anode curved in order to improve the light emission efficiency of the organic light emitting layer is known (e.g. see Patent Documents 2 to 17).
Patent Documents 2 to 4 disclose techniques for improving the viewing angle of an organic EL display, by forming a plurality of concave and convex shapes on the surface of an anode of organic EL element to make an organic light emitting layer concavo-convex.
Patent Documents 5 to 8 disclose techniques of enlarging a surface of an anode by forming fine concave and convex shapes on the surface of an anode of organic EL element to improve the light emission efficiency by increasing a current to supply to an organic light emitting layer.
Patent Document 9 discloses a technique for improving the efficiency of light emission of a pixel by forming concave parts and convex parts in an organic light emitting layer and by suppressing light emission from the convex parts.
Patent Documents 10 and 11 disclose techniques for efficiently utilizing light of the organic light emitting layer by making the organic light emitting layer concavely curved. Further, in Patent Documents 10 and 11, an organic light emitting layer is formed with the deposition method.
Patent Documents 12 to 14 disclose techniques for controlling direction of light by making an anode concavely curved and using an anode as a concave reflection mirror.
Further, in Patent Document 14, an organic light emitting layer is formed by the deposition method.
Patent Document 15 discloses a technique of forming an organic light emitting layer on a substrate having a curved surface and manufacturing a lighting apparatus.
Patent Documents 16 and 17 disclose techniques of forming a plurality of concave and convex shapes on a surface of an anode of organic EL element to reduce power consumption and to increase the aperture ratio.
Patent Document 1: Japanese Patent Application Laid-Open No. 2006-252988
Patent Document 2: International Publication Pamphlet No. 05/107327
Patent Document 3: U.S. Patent Application Publication No. 2008/0024402
Patent Document 4: Japanese Patent Application Laid-Open No. 2005-174914
Patent Document 5: Japanese Patent Application Laid-Open No. 2007-505465
Patent Document 6: U.S. Patent Application Publication No. 2005/0029538
Patent Document 7: Japanese Patent Application Laid-Open No. 2004-335470
Patent Document 8: U.S. Patent Application Publication No. 2004/0222740
Patent Document 9: Japanese Patent Application Laid-Open No. 2004-127575
Patent Document 10: Japanese Patent Application Laid-Open No. 2005-174717
Patent Document 11: Japanese Patent Application Laid-Open No. Hei 10-223368
Patent Document 12: Japanese Patent Application Laid-Open No. 2003-264084
Patent Document 13: U.S. Patent Application Publication No. 2005/0062412
Patent Document 14: Japanese Patent Application Laid-Open No. Hei 10-208875
Patent Document 15: Japanese Patent Application Laid-Open No. Hei 5-47470
Patent Document 16: Japanese Patent Application Laid-Open No. 2005-222935
Patent Document 17: U.S. Patent Application Publication No. 2005/0174041